Essential Question: Will an earthworm move toward a light or dark environment?
Ask the students to think about animals they have observed--perhaps a pet or other outdoor animals. Ask the students to discuss with a partner how animals use their senses to help them survive. Write these behaviors on the board or chart paper. Next, allow the students to predict what they think will happen when an earthworm is placed in the light. Will it try to find a dark environment or stay in the light? How will its senses affect its behavior?
Explain to the students that now each group will build a dark and light environment for the earthworms. They will investigate whether the earthworms will move toward a light or dark environment.
The students will:
- Lay the damp paper towels on the bottom of the plastic pan.
- Cover half of the plastic pan with black construction paper. Use tape to hold the construction paper in place.
- Use the spoon to place 3 earthworms in the center of the pan.
- Make a prediction on the lab sheet to which part of the pan the earthworms will move.
- Turn off the classroom lights. Shine the flashlight directly over the uncovered side of the pan. Use the stopwatch to time 3 minutes. Then observe the location of the earthworms. Record your observations.
- Repeat steps 3-5 three more times. Record your observations.
Facilitate a class discussion using the following questions:
- Did your results support your predictions? Will an earthworm move toward a light or dark environment?
- How was the earthworm's behavior affected by its senses? Sight: Earthworms have no eyes, but they do have light receptors and can tell when they are in the dark, or in the light. Touch: Worms have a brain that connects with nerves from their skin and muscles. Their nerves can detect light.
- Why is being able to detect light so important to a worm? How does it help it survive?
Have students create a list in their Science journals of other animal behaviors that are affected by the use of the animal's senses.